Liquid crystal display devices widely used at present include color filters corresponding to pixels. In particular, color filters corresponding to light's three primary colors of red (R), green (G), and blue (B), are arranged in a predetermined pattern so as to correspond to pixels. A plurality of primary color filters (typically three colors: R, G, and B) form a color display pixel.
In general, liquid crystal display devices each include a pair of substrates and a liquid crystal layer placed therebetween. A color filter layer including a plurality of color filters that are arranged to correspond to pixels as described above is assigned to either one of the substrates. A liquid crystal display device includes, for example, a TFT substrate including circuit elements such as pixel electrodes and TFTs (thin-film transistors), a counter substrate including counter electrodes and color filters, and a liquid crystal layer placed therebetween. The counter substrate, which includes the color filters, is sometimes referred to as a color filter substrate.
However, conventional color filters make use of the absorption of light by pigments and therefore liquid crystal display devices including such color filters have low light use efficiency. In particular, the intensity of light that enters a color filter to pass through the color filter is about ⅓ (one-third) of the intensity of light incident on the color filter, leading to a reduction in lightness. Especially, in a reflective liquid crystal display device using external light, highly visible color display is achieved under bright circumstances and, however, there is a problem in that highly visible color display is unlikely to be achieved under dark circumstances.
Patent Literatures 1 to 3 disclose color display devices, including color liquid crystal display devices, for solving these problems.